Advances in telecommunications and computing technology are leading to the provision of interactive television (TV) on a large scale. Interactive TV involves the use of video gateways and video transport of sufficient bandwidth for video programmers and enhanced video gateway providers to offer their services to residential and business subscribers. Where such facilities are available, subscribers will not only be able to access these services by passively receiving them, but will also be able for the first time to interact with the service providers by communicating requests and commands to the providers via the same path over which the programming services are provided (or even via other paths or drivers).
Interactive TV service is capable of supporting at least the following services: (1) traditional broadcast and cable television programming; (2) video services, such as pay-per-view (PPV), near video-on-demand (NVOD), video-on-demand (VOD), promo channels, electronic program guides, etc.; (3) cable delivered PC-based services; and (4) interactive services, through the use of a combination of compression and digital video technologies. Interactive TV service also permits menuing capabilities and upstream signaling from subscribers to service providers. A subscriber interactive TV connection may, for example, provide subscribers with a screen of available enhanced video gateway providers and/or video programmers and their telephone numbers, or a menu to interactively order services and/or programs.
Interactive television may be provided over any number of paths, including coaxial cable or optical fiber, hybrid fiber/coaxial, or any other suitable path that accommodates sufficient bandwidth for desired analog and digital video channels as well as other telecommunications services. Content Providers may include, for example, providers of interactive or non-interactive over-the-air programming such as commercial television stations, cable programming such as weather, travel and entertainment channels, game channels, and on-line services of various types.
Interactive video enables a subscriber to request that an "interactive session" be established between an "interactive server" or similar platform maintained by an interactive video service provider and a "client" terminal device at the subscriber's premises. An interactive session is a two-way communication relationship, and is a precondition to interactive video services being provided to a subscriber's terminal device. Such a session utilizes the necessary downstream bandwidth and resources (defined below) for delivering interactive video service and the necessary upstream bandwidth from the subscriber's terminal device to issue commands to the interactive server. The terminal device may take the form of what has been termed a "set top box" (STB), or may be any other device capable of performing at least the following functions: (1) exchanging messages (including video-related data) over a network with the interactive server; (2) receiving messages from a user input device, such as a hand-held remote control unit; (3) translating video signals from a network-native format into a format that can be used by the television or display device; and (4) providing a video signal to a television or other display device. A STB may also be capable of performing other functions, such as: (1) inserting alphanumeric or graphical information into the video stream in order to "overlay" that information on the video image; (2) providing graphic or audio feedback to a user; or (3) possibly the most basic function, simply routing a traditional broadcast signal to a viewing device to which the STB is connected.
The STB "client" is "served" by a facility which may be operated and maintained by the video service provider. This "interactive server" provides, in response to a subscriber request, access to an "application," which may be something as straightforward as a video program, or may itself interact with the subscriber by transmitting, for example, a subscriber prompt or menu to allow the subscriber to assert a desired selection from among a set of given commands for the interactive server to carry out.
This added functionality is in large part the result of a historically unprecedented convergence of communications and computing technology. It makes possible, for the first time, features such as the following. In the game media environment, a subscriber may download video games or even play them interactively with the interactive server and/or with other subscribers. An interactive service subscriber may order "time shift TV," in which a particular program may be viewed at a time following its ordinary broadcast time. A subscriber may also selectively view desired parts of transactional, informational or advertising services. For example, a subscriber may view information on the weather predictions for a given location or at a given time, gather information relating to a particular sporting event or team, obtain news on demand, or query a system regarding a particular real estate market. Alternatively, a subscriber may participate in interactive entertainment programs, such as interactive game shows, interactive lottery or gambling, or request musical selections. Subscribers interested in educational programming, such as a school or a family residence, may invoke interactive "edutainment" or "how-to" programs. Interactive communication services, such as on-line services historically provided by the public telephone network, may also be accessed via interactive TV, which permits not only the rapid transfer of files to the subscriber but also interaction with other subscribers.
The combination of broadcast and interactive applications over interactive TV (e.g., interactive programs) creates a new mode of communication in which a user, when informed of the availability of an interactive application relating to the subject matter of a broadcast program, may invoke the application to investigate that subject matter more thoroughly and according to his or her own tastes.
Additionally, television viewers, who are accustomed to choosing at will between the available channels with instantaneous results, will expect to pass from one medium (e.g., broadcast) to another (e.g., interactive) "seamlessly" with the push of a button. To accommodate their viewer's needs, programmers may wish to provide broadcast programming, such as a commercial advertisement or a news program, and make available in the context of that program a related interactive television program.
The means by which interactive television and broadcast television are provided, however, are generally quite different. The two media, for example, are typically supplied from different sources and use different modulation techniques over different transmission paths. The originating source of broadcast programming is likely to be remote from those subscribers interested in invoking an interactive service, making telecommunication between the parties over a dedicated network prohibitively expensive and complex. By contrast, interactive servers, in order to avoid the expense of high bandwidth communications over such distances, can be located geographically close to a corresponding set of subscribers, unlike the programming sources or "Content Providers." An interactive server can therefore efficiently provide exclusive interactive access to a large number of applications by a large number of interactive subscribers.
The technical differences between broadcast programming and interactive applications, combined with the difficulties of providing interactive services at any rate, make the provision of a smooth transition between interactive and broadcast television a difficult proposition and a seamless transition from broadcast television to interactive television and back an elusive goal.